HYDE COUNTY, N.C. (WITN) -Mattamuskeet National Wildlife Refuge says it has experienced a noticeable increase in the number of sick and dead tundra swans this winter and an investigation is underway to determine the cause.
The dead swans have been found around the Entrance Road impoundment, an area frequently visited by bird watchers and photographers.
Mattamuskeet visitors like Lena Keane believe a deep study needs to be done on why this happening so frequently.
“There’s healthy swan right back there, I got out and took a picture,” Keane said. “I held open its wings because I was looking to see how healthy this bird might’ve been.”
The wildlife refuge says thousands of waterfowl use the area in winter, so it would not be unusual to see a few sick or dead birds. However, the numbers have risen well above normal this year and many swans appear unable to make the journey to their northern breeding grounds.
Increased swan deaths were detected in January, prompting refuge staff to submit two swan carcasses to the National Wildlife Health Center for necropsy.
The birds were found to be in generally good nutritional condition and tested negative for avian influenza.
The cause of death was determined to be lead poisoning with lead levels around twice the lethal limit. Field observations of other carcasses match the symptoms for lead poisoning.
“Find out what’s killing these poor birds,” Keane said. “There’s too many of them dead.”
Similar results have been found in birds submitted from this location in previous years.
Prior to the 1991 nationwide ban, lead shot was used extensively for waterfowl hunting.
The refuge says It is likely that the resulting lead shot in the environment is causing this unintended mortality in the swans today.
Refuge staff are currently evaluating options to help reduce similar events in the future.